Systems and methods for a variable geometry turbine nozzle

ABSTRACT

Various systems and methods are described for a variable geometry turbine. In one example, a nozzle vane includes a stationary having a first cambered sliding surface and a sliding vane having a second cambered sliding surface where the second cambered sliding surface includes a flow disrupting feature in contact with the first sliding cambered surface. The sliding vane may be positioned to slide in a direction from substantially tangent along a curved path to an inner circumference of the turbine nozzle and selectively uncover the flow disrupting feature.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 62/082,899, “SYSTEMS AND METHODS FOR A VARIABLE GEOMETRYTURBINE NOZZLE,” filed on Nov. 21, 2014, the entire contents of whichare hereby incorporated by reference for all purposes.

FIELD

The present application relates to variable geometry turbines forturbochargers of internal combustion engines.

BACKGROUND AND SUMMARY

Engines may use a turbocharger to improve engine torque and/or poweroutput density. A turbocharger may include a turbine disposed in linewith the engine's exhaust stream, and coupled via a drive shaft to acompressor disposed in line with the engine's intake air passage. Theexhaust-driven turbine may then supply energy, via the drive shaft, tothe compressor to boost the intake air pressure. In this way, theexhaust-driven turbine supplies energy to the compressor to boost thepressure and flow of air into the engine. Therefore, increasing therotational speed of the turbine may increase boost pressure. The desiredamount of boost may vary over operation of the engine. For example, thedesired boost may be greater during acceleration than duringdeceleration.

One solution to control the boost pressure is the use of a variablegeometry turbine in the turbocharger. A variable geometry turbinecontrols boost pressure by varying the flow of exhaust gas through theturbine. For example, exhaust gas may flow from the exhaust manifoldthrough a turbine nozzle and to the turbine blades. The geometry of theturbine nozzle may be varied to control the angle that exhaust gascontacts the turbine blades and/or to vary the cross-sectional area ofinlet passages, or throat, upstream of the turbine blades. Increasingthe cross-sectional area of the inlet passages may allow more gas toflow through the passages. Furthermore, the angle of incidence of gasflowing across the turbine blades may affect the efficiency of theturbine, e.g., the amount of thermodynamic energy captured from the flowthat is converted to mechanical energy. Thus, the turbine speed andboost pressure may be varied by changing the geometry of the turbinenozzle.

The design of variable geometry turbines has been modified to yieldvarious desirable results. For example, U.S. Patent Application2013/0042608 by Sun et al. discloses systems and methods to vary theangle of incidence of gas flowing across the turbine blade by adjustingthe cross-sectional area of the passages between adjacent nozzle vanes.Herein, an annular turbine nozzle is provided having a central axis anda number of nozzle vanes. Each nozzle vane comprises a stationary vaneand a sliding vane, wherein the sliding vane includes a planar surfacein sliding contact with a planar surface of the stationary vane. Assuch, the nozzle vane may enable a desired angle of incidence and apreferred cross-sectional area of the passages over a range of engineoperating conditions.

The inventors herein have recognized potential issues with the approachidentified above. For example, the sliding vane(s) may intrude at a highflow area of the inlet passages. In this way, intrusion of leading edgesof the sliding vanes may create sub-optimal angles of incidence for theincoming gas and thereby lead to increased aerodynamic flow loss.Moreover, the sliding vane traveling on the planar surface may slide arelatively large distance in the radial direction into the high flowarea of the inlet passage, thereby leading to packaging challenges.

Further, the above methods and systems do not address potential shockwaves generated during certain engine operating conditions, such asengine braking. During engine braking, the exhaust stream may beconstricted, and therefore, shock waves may be generated, leading tostrong interaction and excitation on the turbine blades. The shockwave-induced excitation, also referred to as forced response excitationor fluid structure interaction, may be a source of fatigue on theturbine blades and a limiting factor of further increasing exhaustbraking power of turbocharged engines.

The inventors herein have recognized the above issues and developed anapproach to at least partly address the above issues. As one example, anannular turbine nozzle may be provided, comprising a nozzle vaneincluding a stationary vane attached to a surface of a nozzle wall plateand including a first sliding surface, and a sliding vane including asecond sliding surface including a flow disrupting feature in contactwith the first sliding surface, the sliding vane positioned to slide ina direction from substantially tangent to an inner circumference of theturbine nozzle and selectively uncovering the flow disrupting feature.In this way, the surface treatment may be exposed during variousconditions, such as engine braking, to reduce the intensity of possibleshock waves and excitation on the turbine blades.

For example, the first sliding surface of the stationary vane and thesecond sliding surface of the sliding vane may be cambered surfaces,such that the sliding vane may be positioned to slide along a curvedline matching the cambered surfaces of the first sliding surface and thesecond sliding surface. As such, the sliding vane slides on a curvedpath defined by a curvature, or cambered line, of the first slidingsurface and the second sliding surface. Thus, a desired angle ofincidence may be substantially maintained while simultaneously reducinga radial displacement traveled by the sliding vane during various engineoperating conditions. In this way, exhaust gas expansion losses may bereduced as compared to a sliding vane and stationary vane having planarsliding surfaces.

The above advantages and other advantages, and features of the presentdescription will be readily apparent from the following DetailedDescription when taken alone or in connection with the accompanyingdrawings.

It should be understood that the summary above is provided to introducein simplified form a selection of concepts that are further described inthe detailed description. It is not meant to identify key or essentialfeatures of the claimed subject matter, the scope of which is defineduniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure. Finally, the above explanation does not admit any ofthe information or problems were well known.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example embodiment of a turbocharged engine.

FIG. 2 shows a cross-section of an example embodiment of a turbochargerturbine including a turbine nozzle.

FIG. 3 illustrates a perspective view of an example embodiment of aturbine nozzle and a turbine wheel.

FIG. 4 portrays a magnified view of an example embodiment of a turbinenozzle.

FIG. 5 shows a first example nozzle vane having planar sliding surfacesand a second example nozzle vane have cambered sliding surfaces.

FIG. 6 shows an example turbine nozzle having a nozzle vane of adesirable thickness to chord length ratio.

FIG. 7 shows an example turbine nozzle having nozzle vanes with flowdisrupting features.

FIGS. 8A-8B illustrate example turbine nozzles having exposable flowdisrupting features.

FIG. 9 shows a schematic illustration of a turbine nozzle for a swingvane turbine nozzle.

FIG. 10 illustrates a side schematic view of the example turbine nozzleof FIG. 9.

FIG. 11 shows an example method for a turbocharged engine including aturbine nozzle with swing vane turbine nozzle.

DETAILED DESCRIPTION

The following description relates to systems and methods for variablegeometry turbochargers of internal combustion engines. An example enginewith a turbocharger is illustrated in FIG. 1. The example turbochargerincludes a compressor driven by a turbine, such as the turbineillustrated in FIG. 2. The turbine may include a turbine nozzle and aturbine wheel, such as shown in more detail in FIGS. 3-8. FIG. 3 shows aperspective view of an example embodiment of a turbine nozzle and aturbine wheel. Similarly, FIG. 4 shows a perspective view of an exampleembodiment of the turbine nozzle having nozzle vanes. In one example,each nozzle vane may include a stationary vane and a sliding vane havingflat sliding surfaces, as shown on the top image of FIG. 5. In anotherexample, each nozzle vane may include a stationary vane and a slidingvane having cambered (e.g., curved) sliding surfaces, as shown on thebottom image of FIG. 5. Further, the nozzle vane having a stationaryvane and sliding vane may comprise a desired chord geometry (FIG. 6). Inone embodiment, the turbine nozzle may include a plurality of nozzlevanes, wherein the plurality of nozzle vanes may each include a flowdisrupting surface, or a surface treatment, to reduce shock-inducedexcitation on the turbine blades, as shown in FIG. 7. In anotherembodiment, the sliding vanes may each move to cover and/or uncover theflow disrupting surface on the turbine nozzle (FIG. 8). In yet anotherembodiment, a swing vane turbine nozzle may be provided, wherein thenozzle vanes may comprise a conventional actuation block (top right ofFIG. 9) and/or an actuation block having altered geometry (bottom rightof FIG. 9). Each of the conventional and/or altered geometry actuationblock may rotate, swing, or pivot one or more nozzle vanes. FIG. 10shows a side view of the schematic illustration of the altered geometryactuation block of FIG. 9. Further, a plurality of nozzle vanes in aswing vane turbine nozzle may be adjusted by one or more actuationblocks of FIGS. 9 and 10 for a turbocharged engine (FIG. 11).

FIG. 1 shows an example of a turbocharged engine. Specifically, internalcombustion engine 10, comprising a plurality of cylinders, one cylinderof which is shown in FIG. 1. Engine 10 may be controlled at leastpartially by a control system including controller 12 and by input froma vehicle operator 72 via an input device 70. In this example, inputdevice 70 includes an accelerator pedal and a pedal position sensor 74for generating a proportional pedal position signal PPS. Engine 10includes combustion chamber 30 and cylinder walls 32 with piston 36positioned therein and connected to crankshaft 40. Combustion chamber 30communicates with intake manifold 44 and exhaust manifold 48 viarespective intake valve 52 and exhaust valve 54. Intake manifold 44 isalso shown having fuel injector 68 coupled thereto for delivering fuelin proportion to the pulse width of signal (FPW) from controller 12.

Controller 12 is shown in FIG. 1 as a microcomputer, includingmicroprocessor 102, input/output ports 104, an electronic storage mediumfor executable programs and calibration values shown as read only memorychip 106 in this particular example, random access memory 108, keepalive memory 110, and a data bus. Controller 12 may receive varioussignals from sensors coupled to engine 10, in addition to those signalspreviously discussed, including measurement of inducted mass air flow(MAF) from mass air flow sensor 115; engine coolant temperature (ECT)from temperature sensor 112 coupled to cooling sleeve 114; a profileignition pickup signal (PIP) from Hall effect sensor 118 (or other type)coupled to crankshaft 40; throttle position (TP) from a throttleposition sensor; and absolute manifold pressure signal, MAP, from sensor122. Engine speed signal, RPM, may be generated by controller 12 fromsignal PIP. Further, controller 12 may estimate a compression ratio ofthe engine based on measurements from a pressure transducer positionedin the cylinder 30 (not shown).

The controller 12 receives signals from the various sensors of FIG. 1and employs the various actuators of FIG. 1 to adjust engine operationbased on the received signals and instructions stored on a memory of thecontroller.

Storage medium read-only memory 106 can be programmed with computerreadable data representing instructions executable by processor 102 forperforming the methods.

In a configuration known as high pressure EGR, exhaust gas is deliveredto intake manifold 44 by EGR tube 125 communicating with exhaustmanifold 48. EGR valve assembly 120 is located in EGR tube 125. Statedanother way, exhaust gas travels from exhaust manifold 48 first throughvalve assembly 120, then to intake manifold 44. EGR valve assembly 120can then be said to be located upstream of the intake manifold. There isalso an optional EGR cooler 130 placed in EGR tube 125 to cool EGRbefore entering the intake manifold. Low pressure EGR may be used forrecirculating exhaust gas from downstream of turbine 16 to upstream ofcompressor 14 via valve 141.

Pressure sensor 115 provides a measurement of manifold pressure (MAP) tocontroller 12. EGR valve assembly 120 has a valve position (not shown)for controlling a variable area restriction in EGR tube 125, whichthereby controls EGR flow. EGR valve assembly 120 can either minimallyrestrict EGR flow through tube 125 or completely restrict EGR flowthrough tube 125, or operate to variably restrict EGR flow. Vacuumregulator 124 is coupled to EGR valve assembly 120. Vacuum regulator 124receives actuation signal 126 from controller 12 for controlling valveposition of EGR valve assembly 120. In one embodiment, EGR valveassembly is a vacuum actuated valve. However, any type of flow controlvalve may be used, such as, for example, an electrical solenoid poweredvalve or a stepper motor powered valve.

Turbocharger 13 has a turbine 16 coupled to exhaust manifold 48 and acompressor 14 coupled in the intake manifold 44 via an intercooler 132.Turbine 16 is coupled to compressor 14 via a drive shaft 15. Air atatmospheric pressure enters compressor 14 from passage 140. Exhaust gasflows from exhaust manifold 48, through turbine 16, and exits passage142. In this manner, the exhaust-driven turbine supplies energy to thecompressor to boost the pressure and flow of air into the engine. Theboost pressure may be controlled by the rotational speed of turbine 16which is at least partially controlled by the flow of gasses throughturbine 16.

The flow of exhaust gases through turbine 16 may be further illustratedby the example embodiment of turbine 16 in FIG. 2. Turbine 16 mayinclude a volute or housing 202 that encloses a turbine nozzle 210 and aturbine wheel 220 having turbine blades 222. For example, housing 202may include an inlet passage 204 in communication with turbine nozzle210. Turbine nozzle 210 may be in communication with inlet passage 204.Thus, exhaust gas may flow from exhaust manifold 48, through inletpassage 204, through turbine nozzle 210, across turbine wheel 220 andturbine blades 222 into passage 206, and out to passage 142. Further,the flow of exhaust gases, e.g. the expansion of gases, through turbine16 may be controlled by varying the geometry of turbine nozzle 210, andthus, the rotational speed of turbine 16 may be controlled.

In one embodiment, turbine nozzle 210 may be generally annular and sharea central axis 230 with turbine wheel 220 and drive shaft 15. In otherwords, turbine wheel 220 and turbine nozzle 210 may be coaxial andconcentric. Turbine nozzle 210 may include an annular unison ring 240,an annular nozzle wall plate 250, and one or more nozzle vanes 260. Inone embodiment, unison ring 240 and nozzle wall plate 250 may form asupport and control structure for nozzle vane 260. As such, in oneexample, the shape of nozzle vane 260 may be adjusted by rotating one orboth of unison ring 240 and nozzle wall plate 250.

A geometry of each nozzle vane 260 may be adjusted to control the flowof gases through turbine nozzle 210. For example, in a split slidingnozzle vane turbine (SSVNT), a length of nozzle vane 260 may be adjustedto control the flow of gases through turbine nozzle 210. In thisexample, a sliding vane of the nozzle vane 260 may slide in a directiontangentially from an outer circumference of the nozzle wall plate 250.The aforementioned arrangement may be herein referred to as aconventional sliding vane embodiment.

In another embodiment contrasting the conventional sliding vaneembodiment, a sliding vane of the nozzle vane 260 may slide back intoand out from a recess or well (as shown in reference to FIG. 8) over arange of engine operating conditions. More specifically, the slidingvane of the nozzle vane 260 may slide axially into the nozzle wall plate250, for example, in a direction parallel to the central axis 230 ratherthan tangentially from the outer circumference of the nozzle wall plate250.

In yet another embodiment, a swing or pivot nozzle vane turbine may beprovided in place of the SSVNT. Nozzle vanes 260 of a swing or pivotnozzle vane turbine may pivot around an axis parallel with the centralaxis 230. The swing or pivot nozzle vane turbine, as shown below inreference to FIGS. 9-11, may vary the flow of exhaust gas throughturbine 16 by controlling an angle at which exhaust gas strikes theturbine blades 222. Additionally, the swing nozzle vane turbine may varythe flow of exhaust gas through turbine 16 by controlling across-sectional area of inlet passages 204 between nozzle vanes 260upstream from the turbine blades 222 through which the exhaust flowpasses. As such, nozzle vanes 260 may be configured to pivot in onedirection to increase the cross-sectional area of inlet passages 204upstream of the turbine 16, thereby decreasing an angle of incidence ofgas flowing across the turbine blades 222. The nozzle vanes 260 may alsobe configured to pivot in the opposite direction to decreases thecross-sectional area of inlet passages 204 to the turbine wheel. As aresult, the angle of incidence of exhaust gas flowing across the turbineblades 222 may be increased.

Regardless of a type of turbine nozzle described above, varying thegeometry of nozzle vane 260 and/or the orientation of the nozzle vane260 may vary the cross-sectional area of the inlet passages 204 ofturbine nozzle 210. In one embodiment, the inlet passage 204 may includefour sides. For example, a first side of the inlet passage 204 may beformed by a surface 252 of nozzle wall plate 250 and a second side ofthe inlet passage 204 may be formed by a surface 208 of turbine housing202. The third side and fourth side may each be formed by a surface ofadjacent nozzle vanes. As such, lengthening nozzle vane 260 may adjustthe cross-sectional area of inlet passages 204 of turbine nozzle 210 andthe volumetric flow of gas through inlet passages 204.

In another embodiment, axial movement of one or both of nozzle wallplate 250 and turbine housing 202 may further be used to vary thecross-sectional area of the inlet passages 204 of turbine nozzle 210.For example, a distance between nozzle wall plate 250 and turbinehousing 202 may be varied during certain engine operating conditions,such that the nozzle wall plate 250 may be moved for the distancerelative to turbine housing 202. Thus, the cross-sectional area of theinlet passages 204 of the turbine nozzle 210 of a swing nozzle typeturbine may also be controlled by varying additional turbine components.

The geometry and adjustment of nozzle vane 260 may be furtherillustrated in FIG. 3. FIG. 3 shows a perspective view of an examplesliding vane turbine nozzle 210 and turbine wheel 220, where part ofnozzle wall plate 250 is cut-away, e.g., removed, for illustrationpurposes at cut-lines 302 and 304. Thus, details of unison ring 240 thatare covered by nozzle wall plate 250 in an assembled turbine nozzle 210are shown in FIG. 3. Turbine nozzle 210, unison ring 240, and nozzlewall plate 250 may be generally annular or ring shaped with an innercircumference and an outer circumference. In one embodiment, turbinenozzle 210, unison ring 240, and nozzle wall plate 250 are coaxial.Further, inner circumferences of turbine nozzle 210, unison ring 240,and nozzle wall plate 250 may be the same. In one embodiment, the outercircumferences of turbine nozzle 210, unison ring 240, and nozzle wallplate 250 may be the same.

Nozzle vane 260 may include a stationary vane 310 and a sliding vane320. In one embodiment, the length of nozzle vane 260 may be adjusted bymoving (e.g., sliding) one or both of the stationary vane 310 andsliding vane 320 relative to each other. For example, sliding vane 320may be configured to move and stationary vane 310 may be attached to orintegral to nozzle wall plate 250. Attachment of stationary vane 310 tonozzle wall plate 250 may reduce clearance between stationary vane 310and nozzle wall plate 250. In this way, aerodynamic losses may bereduced when exhaust gases flow past stationary vane 310. Stationaryvane 310 may include a sliding surface 312 in sliding contact with asliding surface 322 of sliding vane 320. In one embodiment, slidingsurface 312 and sliding surface 322 may be substantially perpendicularto surface 252 of nozzle wall plate 250. For example, the angle betweeneach of sliding surface 312 and sliding surface 322, and surface 252 maybe 90 degrees. In another example, the angle between each of slidingsurface 312 and sliding surface 322, and surface 252 may be between 80and 100 degrees. Therefore, sliding surfaces 312 and 322 may be paralleland planar.

In another embodiment, sliding surface 312 of stationary vane 310 andsliding surface 322 of sliding vane 320 may be cambered (e.g., curved),and not planar. As such, sliding surface 312 of the stationary vane 310and sliding surface 322 of sliding vane 320 may be substantiallycomplementary to one another. For example, sliding surface 322 of thesliding vane 320 may be convex and sliding surface 312 of the stationaryvane 310 may be correspondingly concave, as shown in below in referenceto FIG. 5. Sliding surface 322 may be positioned to slide along a curvedtangential path matching the same cambered surfaces of the slidingsurfaces 312 and 322. In an example, the sliding vane 320 slides on acurved path defined by a curvature of the first sliding surface (e.g.,sliding surface 312 of stationary vane 310) and the second slidingsurface (e.g., sliding surface 322 of sliding vane 320).

In this embodiment, extension or elongation of the nozzle vane 260 alongcambered sliding surfaces 312 and 322 may reduce a radial displacementof the sliding vane 320 during low exhaust flow conditions (e.g., duringlight or low engine load, low engine speed, and/or low enginetemperature) compared to extension or elongation of a nozzle vane havingflat and planar sliding surfaces. As such, packaging burdens may bereduced due to the decreased spatial displacement of the camberedsliding surfaces, as discussed below in reference to FIG. 5.

In one embodiment, sliding vane 320 may be positioned to move or slideas unison ring 240 is rotated. For example, unison ring 240 may berotated via an actuation arm 340 extending in a radial direction fromunison ring 240. Unison ring 240 may include a slot 330 shaped toreceive and direct the position of a bearing 350. Bearing 350 may beconfigured to receive an actuation pin 324 of sliding vane 320. Forexample, actuation pin 324 may extend from sliding vane 320 through aslot in nozzle wall plate 250 to be received by bearing 350. Thus,sliding vane 320 may be constrained to move within a range determined bythe length and position of the slot in nozzle wall plate 250 and thelength and position of slot 330.

In an alternative embodiment, sliding vane 320 may be positioned to moveas unison ring 240 is rotated via an actuator output shaft (not shown),which is linked to a stirrup member (not shown). The stirrup member mayengage with axially extending guide rods (not shown) that support thenozzle ring. As such, the actuator output shaft, driven by a pneumatic,electric, and/or or mechanical mechanism, may enable the turbine nozzleto be moved. It will be appreciated that details of the nozzle ringmounting and guide arrangements may differ from those illustrated.

Turning now to FIG. 4, an exploded view of an example turbine nozzle isshown, which may further illustrate components of turbine nozzle 210,including slot 410 in nozzle wall plate 250. In one embodiment, slot 410may extend to the outer circumference of nozzle wall plate 250. Whenturbine nozzle 210 is assembled, slot 410 of nozzle wall plate 250 andslot 330 of unison ring 240 may cross. Actuation pin 324 may extend fromsliding vane 320 through nozzle wall plate 250 and unison ring 240 atthe cross-point of slots 330 and 410. When unison ring 240 is rotated ina first direction relative to nozzle wall plate 250 about central axis230, the cross-point may move outward toward the outer circumference ofnozzle wall plate 250. Similarly, when unison ring 240 is rotated in anopposite, second direction relative to nozzle wall plate 250, thecross-point may move inward toward the inner circumference of nozzlewall plate 250. Thus, the position of sliding vane 320 may be adjustedby rotating unison ring 240. For example, in one embodiment, the slidingsurface 322 of sliding vane 320 may be moved in a curved radialdirection on turbine nozzle 210 along sliding surface 312. In anotherembodiment, sliding vane 320 may be moved in a curved direction withoutpivoting.

The sliding of sliding vane 320 as described above during various engineoperating conditions may control the flow of exhaust gas travelingthrough turbine nozzle 210. In this way, boost pressure of intakemanifold 44 may be controlled. Specifically, the flow of exhaust gasthrough turbine nozzle 210 may be controlled by adjusting a length ofnozzle vane 260, which may vary the cross-sectional area of inletpassages 204 of turbine nozzle 210.

Exhaust gas flowing through turbine nozzle 210 may include soot andhydrocarbons that may be deposited on sliding surfaces 312 and 322. Thedeposits may cause increased resistance, or sticking, when sliding vane320 slides upon and against stationary vane 310. Thus, it may bedesirable to reduce the soot and hydrocarbon deposits on slidingsurfaces 312 and 322 during operation of the engine. In one example, thesliding motion of sliding surface 322 against sliding surface 312 may beused to remove the deposits.

As such, in one embodiment, stationary vane 310 may be made of a firstmaterial and sliding vane 320 may be made of a different, secondmaterial. Further, the first material and/or second material may beabrasive. For example, stationary vane 310 may be ceramic orceramic-coated, and sliding vane 320 may be steel. As another example,stationary vane 310 may be steel, and sliding vane 320 may be ceramic orceramic-coated. Further, one or both of sliding surfaces 312 and 322 mayinclude a texture. For example, a coarse texture on sliding surface 312of the stationary vane 310 may reduce the surface area in contact withsliding surface 322. As such, the course texture on sliding surface 312of stationary vane 310 may reduce resistance when the sliding vane 320is moving or sliding in contact with stationary vane 310. Additionallyor alternatively, sliding surface 322 of sliding vane 320 may also havea coarse texture or pattern, thus further reducing resistance when thesliding vane 320 is moving or sliding against and in contact withstationary vane 310. In this way, a textured surface may also rub off orreduce soot deposits collected one or more of the textured surfaces onone or more of the sliding surfaces (e.g., sliding surface 312 ofstationary vane 310 and sliding surface 322 of sliding vane 320).

In another embodiment, sticking of the moving sliding vane 320 may bereduced by increasing a clearance distance between nozzle wall plate 250and each nozzle vane 260 during certain engine operating conditions inan engine having a swing nozzle vane turbine and/or SSVNT. The increasedclearance distance may be achieved via implementation of an actuationblock, the actuation block having a substantially rhomboid-shape and/orparallelogram-shaped cross-section. In one example, the actuation blockmay be coupled to the actuation pin 324 of sliding vane 320. As such,the actuation block may be configured to produce a transverse force orpressure on a location of the actuation pin 324 opposite the slidingvane 320, as described below in reference to FIGS. 9-11. In otherexamples, other suitable actuator(s) (e.g., an actuation yoke) may beemployed to apply a force to nozzle vane 260 and enable nozzle vane 260to move along central axis 230. As a result, a plurality of nozzle vanes260 may be moved away from the surface 252 of nozzle wall plate 250during one or more engine operating conditions. In this way, sticking ofthe nozzle vanes 260 to surface 252 may be reduced during engineoperating conditions that may be prone to vane sticking, e.g., duringhigh engine temperatures and/or high engine load.

Turning now to FIG. 5, at the top is a schematic illustration of nozzlevane 260 having planar sliding surfaces 312 and 322, as referenced inFIG. 3 above. At the bottom of FIG. 5 is a schematic illustration of anozzle vane 500 comprising a stationary vane 502 and sliding vane 506,wherein the stationary vane 502 has a cambered sliding surface 504, andthe sliding vane 506 has a cambered sliding surface 508. In oneembodiment, nozzle vane 500 may be included as an alternative to nozzlevane 260 on turbine nozzle 210 having annular nozzle wall plate 250.Sliding vane 320 of nozzle vane 260 may slide in contact with andagainst stationary vane 310 of nozzle vane 260 along sliding surfaces312 and 322, as described above in reference to FIG. 3. Similarly,sliding vane 506 may slide in contact with and against stationary vane502 along sliding surface 504 of stationary vane 502 and sliding surface508 of sliding vane 506.

Nozzle vane 260 may be adjusted to a minimum length 530, while nozzlevane 500 may be adjusted to a minimum length 510. In one example, whennozzle vane 260 is adjusted to minimum length 530, nozzle vane 260 maybe referred to as being in a small vane opening position. Likewise, whennozzle vane 500 is adjusted to minimum length 510, nozzle vane 500 maybe referred to as being in the small vane opening position. In oneexample, minimum lengths 510 and 530 are substantially the same, asminimum lengths 510 and 530 may each reflect a length of the nozzle vanewhen sliding vane 320 and sliding vane 506 are substantially overlappingtheir respective stationary vane (e.g., stationary vane 310 alongsliding surface 322 for sliding vane 320 of nozzle vane 260, andstationary vane 502 along sliding surface 508 for sliding vane 506 ofnozzle vane 500). In this example, a trailing edge 560 of nozzle vane260 and a trailing edge 580 of nozzle vane 500 may be proximal turbinewheel 220. In other words, nozzle vane 260 and nozzle vane 500 may beadjusted to the minimum length 530 and minimum length 510, respectively,when sliding vane 320 and sliding vane 506 are each adjusted to an endof its range closest to turbine wheel 220. As a result, the small vaneopening position of nozzle vane 260 and/or nozzle vane 500 allows for alarger cross-sectional area of inlet passage 204 to the turbine blades222. In this way, the small vane opening position of nozzle vane 260and/or nozzle vane 500 may be desirable during low engine loadconditions.

In another embodiment, nozzle vane 500 having cambered sliding surface508 on the sliding vane 506 and cambered sliding surface 504 on thestationary vane 502 may be adjusted to a maximum length 520. Nozzle vane500 adjusted to the maximum length 520 is shown as dashed lines (bottomof FIG. 5). Likewise, the nozzle vane 260 having planar sliding surface312 on stationary vane 310 and planar sliding surface 322 on slidingvane 320 may be adjusted to a maximum length 540. Nozzle vane 260adjusted to the maximum length 540 is shown as dashed lines (top of FIG.5). Herein, when nozzle vane 260 is adjusted to maximum length 540,nozzle vane 260 may be referred to as being in a large vane openingposition. Similarly, when nozzle vane 500 is adjusted to maximum length520, nozzle vane 500 may be referred to as being in the large vaneopening position. In this example, maximum length 520 may be less thanmaximum length 540, as shown by a distance 590, wherein distance 590 maybe the difference in length between maximum length 520 of nozzle vane500 and maximum length 540 of nozzle vane 260. Consequently, nozzle vane500 having the shorter maximum length 520 as compared to nozzle vane 260having the longer maximum length 540 may allow for reduced radialdisplacement when nozzle vane 500 is implemented in a turbocharger, andwhen sliding vane 506 is substantially extended in its range and aleading edge 570 of the nozzle vane 500 is closest to an outercircumference of the nozzle wall plate 250 of the turbine 16.Consequently, packaging burdens may be reduced.

Said another way, nozzle vane 260 and nozzle vane 500 may each beadjusted to maximum length 540 and maximum length 520, respectively,when sliding vane 320 of nozzle vane 260 and sliding vane 506 of nozzlevane 500 are each adjusted to an end of its range farthest from theturbine blades 222. As a result, the large vane opening position of eachof the nozzle vane 260 and/or nozzle vane 500 may allow for a smallercross-sectional area of the inlet passage 204 to the turbine blades 222.In this way, the large vane opening position of nozzle vane 260 and/ornozzle vane 500 may be desirable during low engine load and low enginespeed conditions.

In one embodiment, sliding of the sliding vane from the small vaneopening position to the large vane opening position of each of thenozzle vane 260 and nozzle vane 500 may at least partially control anexposure of a flow disrupting feature positioned on or around one ormore of the nozzle vanes over various operation conditions, as discussedbelow with reference to FIGS. 7 and 8. The flow disrupting feature mayreduce an intensity of a possible shock wave and excitation on theturbine blades when the cross-sectional area of the inlet passages 204is reduced, thereby constricting exhaust flow during certain engineoperating conditions such as engine braking.

As an example, in the large vane opening position of nozzle vane 500wherein the sliding vane 506 extends to the maximum length 520 and awayfrom the stationary vane 502, the flow disrupting feature may beuncovered and exposed to exhaust gas flow. Alternatively, in the smallvane opening position of nozzle vane 500 wherein the sliding vane 506 isnot extended away from the stationary vane 502 and the nozzle vane 500is at the minimum length 510, the flow disrupting feature may be fullycovered by sliding vane 506 such that the flow disrupting feature is notexposed to the exhaust gas flow traveling therethrough. In anotherexample, in the large vane opening position of 260 wherein the slidingvane 320 extends to the maximum length 540 and away from the stationaryvane 310, the flow disrupting feature may be uncovered and exposed toexhaust gas flow. Alternatively, in the small vane opening position ofnozzle vane 260 wherein the sliding vane 320 is not extended away fromthe stationary vane 310 and the nozzle vane 260 is at the minimum length530, the flow disrupting feature may be fully covered by sliding vane320 such that the flow disrupting feature is not exposed to the exhaustgas flow traveling therethrough.

Further, planar sliding surfaces 312 and 322 of nozzle vane 260 may besubstantially tangent to an inner circumference of nozzle wall plate250. For example, leading edge 550 of sliding vane 320, when adjusted tomaximum length 540, may be within zero to sixty degrees (e.g., zero totwenty) relative to tangent of a circumference of nozzle wall plate 250.Similarly, cambered sliding surfaces 504 and 508 of nozzle vane 500 maybe substantially tangent to the inner circumference of nozzle wall plate250. For example, leading edge 570 of sliding vane 506, when adjusted tomaximum length 520, may be within zero to sixty degrees (e.g., zero totwenty) relative to tangent of the circumference of nozzle wall plate250.

In another embodiment, leading edge 570 of sliding vane 506, whenadjusted to maximum length 520, may be within zero to fifteen degreesrelative to tangent of the circumference of nozzle wall plate 250.Consequently, the leading edge of a nozzle vane having cambered slidingsurfaces (e.g., nozzle vane 500) may result a smaller angle relative tothe circumference of nozzle wall plate 250 when the nozzle vane 500 isadjusted to maximum length 520. As such, there may be a smaller radialdisplacement into the inlet passage 204 as compared a nozzle vane havingplanar sliding surfaces (e.g., nozzle vane 260).

In other words, the leading edge 550 of sliding vane 320, when adjustedto maximum length 540 may reach an outer circumference of the nozzlewall plate, such that the leading edge 550 may intrude into the inletpassages 204. In contrast, the leading edge 570 of sliding vane 506,when adjusted to maximum length 520, may not reach an outercircumference of the nozzle wall plate 250. Thus, intrusion into theinlet passages 204 with the nozzle vane 500 having cambered slidingsurfaces 504 and 508 may be reduced. In this way, the cambered slidingsurfaces (e.g., sliding surfaces 504 and 508 of nozzle vane 500) mayreduce aerodynamic flow losses, thereby increasing the rotative power ofthe turbine.

Of note, the shape, orientation, direction of vane extension, angle ofincidence, and/or any other relevant geometries and parameters of thesliding and stationary surfaces and/or sliding and stationary vanes mayvary depending on desired functions in a SSVNT or a conventional swingnozzle vane turbine.

In this way, the nozzle vane 500 having cambered sliding surfaces 504and 508 may reduce an intrusion of the leading edge 570 of nozzle vane500 into the inlet passage 204 due to the smaller radial displacementduring low engine temperature, low engine speed, and/or low engine loadoperating conditions. This may result in reduction of sub-optimal anglesof incidence for the incoming exhaust gas to the turbine blades 222, andthus, increase turbine efficiency. Further, the smaller radialdisplacement into the inlet passage 204 of the nozzle vane 500 havingcambered sliding surfaces 504 and 508 may reduce a need for an enlargedvolute (e.g., turbine housing 202). An enlarged turbine housing 202 mayhinder packaging, reduce pulsed flow energy utilization, and increaseheat loss and penalties during transient responses and warm-up.

FIG. 6 portrays nozzle vane 500 and dimensions of nozzle vane 500 thatmay affect aerodynamic properties of turbine nozzle 210. The topillustration of FIG. 6 shows an example embodiment of nozzle vane 500 sothat various nozzle vane characteristics may be defined contextually.The bottom illustration of FIG. 6 shows contextually where nozzle vane500 is positioned on a turbine nozzle 608, as well as other relevantparameters to define the various desirable vane characteristics.

Nozzle vane 500 may include rounded leading edge 570 and the taperedtrailing edge 580, as described in reference to FIG. 5. A chord 610 ofnozzle vane 500 having a longitudinal length 606 may extend betweenleading edge 570 and trailing edge 580. A curved or cambered plane 604may extend between leading edge 570 and trailing edge 580. Plane 604 maybe a camber line of the nozzle vane 500. In an example, plane 604 maysubstantially coincide with sliding surface 504 of stationary vane 502and sliding surface 508 of sliding vane 506. In one embodiment, chord610 may form an angle 612 with plane 604 at the interface of slidingsurface 504 of stationary vane 502 and sliding surface 508 of slidingvane 506 of nozzle vane 500. In an example, angle 612 may be within ±45degrees (e.g., within a range of approximately −45 degrees to 45degrees) with plane 604.

In an embodiment, longitudinal length 606 of chord 610 may comprise alength of 70-90% of half the length R2 of a nozzle outlet radius 660,wherein the length R2 of the nozzle outlet radius 660 may be definedfrom a centerline of the turbine nozzle to an outer circumference 640 ofthe nozzle wall plate 250. In another example, plane 604 may be 6 to 7times greater than half the length of the nozzle outlet radius R2.

In addition, a maximum nozzle thickness 616, herein defined as a heightof the thickest part of nozzle vane 500 along a vertical axis (thevertical axis perpendicular to a central axis of the turbine nozzle),may be located at or near (e.g., proximal) the leading edge 570 ofnozzle vane 500. In one example, a ratio of the maximum nozzle thickness616 of the nozzle vane 500 at the leading edge 570 to the length 606 ofthe chord 610 may be greater than 0.35. It shall be noted that chord 610having the aforementioned geometries may also apply to a conventionalswing nozzle vane turbine with nozzle vanes that pivot or swing toadjust the cross-sectional area of the inlet passage 204.

The aforementioned nozzle vane configurations may reduce the incidenceloss at the leading edge 570 of the nozzle vane 500 when the nozzle vane500 slides to the large vane opening position. In this way, there may bea reduction in aerodynamic performance penalty when nozzle vane 500 isextended to the large vane opening position during low engine loadand/or low engine temperature conditions. As such, aerodynamicefficiency may be improved at both small vane opening position and largevane opening position while forced back-responses may be simultaneouslylessened.

In sum, the nozzle vane geometry disclosed herein having the ratio ofthe maximum nozzle thickness 616 to chord length 606 (i.e., a ratiogreater than approximately 0.35) may achieve desirable aerodynamicperformance with reduced forced response for both swing nozzle vaneturbines and SSVNTs. There may also be reductions in the variation ofangles of incidence at the leading edges of the nozzle vanes and theflow angles at the trailing edges of the nozzle vanes when the nozzlevanes are adjusted. As a result, turbine aerodynamic efficiency may beincreased, which may translate to improvements in fuel economy.

FIG. 7 is an example front view of a turbine wheel, such as turbinewheel 220, surrounded by a plurality of nozzle vanes. The nozzle vanesshown in FIG. 7 may be an alternative embodiment of the nozzle vane 260described in FIGS. 3-5, and thus are numbered as such. In oneembodiment, a nozzle vane having planar sliding surfaces (e.g., nozzlevane 260) may be adjusted to minimum length 530 of FIG. 5. In analternative embodiment (not shown), a nozzle vane having camberedsliding surfaces (e.g., nozzle vane 500) may be provided instead of thenozzle vane having planar sliding surfaces as shown in FIG. 7. In oneexample, sliding vane 320 may slide against and in contact withstationary vane 310 along a plane 706. Plane 706 may substantiallycoincide with sliding surface 312 of stationary vane 310 and slidingsurface 322 of sliding vane 320. Moreover, plane 706 may besubstantially tangent to inner circumference 630 of nozzle wall plate250. When sliding vane 320 is adjusted to an end of its range closest tothe outer circumference 640 of nozzle wall plate 250, nozzle vane 260may be adjusted to maximum length 540.

In the example nozzle vane shown in FIG. 7, nozzle vane 260 may includea first gas surface 710 and a second gas surface 720. Each of gassurface 710 and 720 may direct a flow of exhaust gases towards theturbine blades 222 of turbine wheel 220 of the turbocharger from leadingedge 550 towards trailing edge 560. The shape and orientation of thefirst gas surface 710 of stationary vane 310 and the second gas surface720 of sliding vane 320 may affect the angle of incidence of gas flowingacross turbine blades 222. For example, first gas surface 710 ofstationary vane 310 and the second gas surface 720 of sliding vane maybe configured such that the gases exit turbine nozzle 210 and flowacross the turbine blades 222 at an angle of incidence substantiallyperpendicular to turbine blades 222 and substantially tangential to theinner circumference 630.

Gas surfaces 710 and 720 may be curved or have other suitablegeometries. For example, gas surfaces 710 and 720 may trace an arc witha single axis of curvature. As another example, the gas surfaces 710 and720 may include a convex and a concave portion as far as the flowpassage converges along a flow direction. For example, nozzle vane 260may be curved wedge shaped with a thick end near leading edge 550 and anarrow end near trailing edge 560.

Further, in an example, stationary vane 310 may be attached to turbinenozzle 210 and the geometry of gas surface 710 may be unchanging whenthe length of nozzle vane 260 is adjusted. As such, the geometry ofleading edge 550 of sliding vane 320 and the geometry of taperedtrailing edge 560 of stationary vane 310 may potentially reducevariation in the angle of incidence as nozzle vane 260 is adjusted inlength. Thus, gas flowing near gas surface 710 of stationary vane 310may be guided toward turbine blades 222 with little variation. In thisway, turbine efficiency may be increased over a wider range of engineoperating conditions.

As shown in FIG. 7, inlet passages 204 through turbine nozzle 210 may beformed between adjacent nozzle vanes 260. For example, inlet passage 204may be formed between gas surface 710 of stationary vane 310 and gassurface 720 of sliding vane 320 of nozzle vane 260. In anotherembodiment, inlet passages 204 may be formed between gas surfaces ofstationary vane 502 and sliding vane 506 of nozzle vane 500. Gas may beguided by gas surfaces 710 and 720 as gas flows through the passagesfrom leading edge 550 of nozzle vane 260 toward trailing edge 560 ofnozzle vane 260. The leading edge 550 of nozzle vane 260 may bepositioned to face outer circumference 640 and the trailing edge 560 ofnozzle vane 260 may be positioned to face inner circumference 630. Byorienting each nozzle vane 260 substantially tangent to innercircumference 630 of nozzle wall plate 250, the inlet passage 204 may benarrowed as gas flows through turbine nozzle 210 from outercircumference 640 to inner circumference 630.

As discussed above, nozzle vane 260 of turbine nozzle 210 may be variedin response to different engine operating conditions. For example, itmay be desirable to adjust the amount of boost pressure to the engineduring different engine operating conditions. By adjusting the length ofsliding nozzle vane 260, the flow of gas through turbine nozzle 210 maybe varied and the boost pressure of intake manifold 44 may be adjusted.For example, nozzle vane 260 may be lengthened by moving sliding vane320 toward inner circumference 630 of nozzle wall plate 250. In thismanner, the narrower part of the inlet passage having a width, such as awidth 708, between adjacent nozzle vanes, e.g. between gas surfaces 710and 720, may be further narrowed to a width less than width 708. Thus,the cross-sectional area of the inlet passage 204 may be reduced byincreasing the length of nozzle vane 260. In this way, exhaust gases maybe accelerated as the gas flows from outer circumference 640 to innercircumference 630. For example, gas may be accelerated as the gas flowsthrough the inlet passage from outer circumference 640 to a narrowerpoint of the inlet passage having a width 708.

However, during certain engine operating conditions, such as exhaustbraking (i.e. when the engine is used to slow a vehicle in order toreduce wear on a vehicle's brakes and/or to reduce the amount of heatthat may be generated if only the vehicle brakes are used to slow orstop the vehicle), the sliding vane 320 may be extended (and moved awayfrom the stationary vane 310) to the large vane opening position. As aresult, the cross-sectional area of inlet passage 204 may decrease andmay constrict the exhaust flow. Thus, backpressure in the inlet passage204 may increase. In response, pistons 36 may be forced to work againstthe backpressure to expel the combusted gas from the cylinder(s), thusslowing the engine 10 and the vehicle.

Therefore, in some examples, a flow disrupting feature 702 may beincluded on one or more stationary or sliding surfaces (e.g., surfaces312, 322, 504 and/or 508) of one or more nozzle vanes 260 (and/or nozzlevanes 500). The flow disrupting feature 702 may reduce an intensity of apossible shock wave and subsequent excitation on turbine blades 222.More specifically, the flow disrupting feature 702 positioned on one ormore nozzle vanes may effectively disperse sharp and strong shock wavesinto weakened shock waves that spread over a finite area during certainoperating conditions, such as when the nozzle vane is in the smallopening vane position during engine braking Said another way, the flowdisrupting feature 702 may reduce a shock wave that may occur when theexhaust gas passes through constricted inlet passages upstream of theturbine.

In one example, the flow disrupting feature 702 may be on a firstsliding surface (e.g., sliding surface 322) of the sliding vane 320,such that when the first sliding surface slides against a second slidingsurface (e.g., sliding surface 312) of the stationary vane 310, the flowdisrupting feature 702 may be hidden and covered. In another example,the flow disrupting feature 702 may be on the second sliding surface(e.g., sliding surface 312) of the stationary vane 310, such that whenthe first sliding surface of the sliding vane 320 slides against thesecond sliding surface of the stationary vane 310, the flow disruptingfeature 702 may be hidden and covered. In this way, the flow disruptingfeature 702 may be preferentially exposed during one or more desirableconditions. In another embodiment, the flow disrupting feature 702 maybe disposed on a wall plate, such as nozzle wall plate 250, as describedbelow with reference to FIG. 8B.

In one embodiment, the flow disrupting feature 702 may be a plurality offlow disrupting features. In other examples, the flow disrupting feature702 may be arranged on a swing or pivot nozzle vane turbine and/orSSVNT.

In some examples, each flow disrupting feature 702 may occupy all orsome portion of the sliding surface of one or more nozzle vanes 260. Forexample, each flow disrupting feature 702 may occupy approximately 10%to 40% of a surface area of trailing edge 560 or leading edge 550 on afirst side (e.g., a side of the nozzle vane facing towards the turbinewheel) or a second side (e.g., a side of the nozzle vane facing towardsthe turbine housing) of each of the plurality of nozzle vanes 260.

In one embodiment, the flow disrupting feature 702 may include two ormore parallel grooves, as shown in FIG. 7. For example, the parallelgrooves may have a substantially triangular with a pointed bottom and/orrectangular cross-section with a substantially flat bottom. In anotherexample, the parallel grooves may form a specific angle with a bottomsurface (not shown) of the trailing edge 560. For example, the parallelgrooves may be substantially parallel with a bottom surface of thetrailing edge 560.

Furthermore, in some embodiments, the flow disrupting feature 702 mayinclude dimples (not shown). For example, the flow disrupting feature702 may include one or more substantially round dimples and/orsubstantially rectangular dimples. In yet another example, the flowdisrupting feature 702 may form angled or straight valleys (not shown).In yet another example, the flow disrupting feature 702 may include acombination of grooves and dimples, or may include other shapesincluding, for example, holes, or bumps, and the like, and/or variouscombinations of various features of different shapes. The patternsformed on the nozzle vanes 260 may be substantially similar in size,orientation and shape amongst the plurality of flow disrupting features702. The flow disrupting feature 702 may be arranged parallel and/orperpendicular to the edges of the nozzle vane, or may be arranged at anangle. In addition, the flow disrupting feature 702 may be locatedsubstantially adjacent to a first side (not shown) of each of theplurality of nozzle vanes, the first side being a side facing the hub ofthe turbocharger 13. On the other hand, the flow disrupting feature 702may be located substantially adjacent to a second side (not shown) ofeach of the plurality of nozzle vanes, the second side being a sidefacing the shroud of the turbocharger 13.

In one embodiment, the flow disrupting feature 702 may arranged on thesurface area of the first side of the sliding vane 320 along thetrailing edge 560, as depicted in FIG. 7. Moreover, the flow disruptingfeature 702 may be on the sliding surface 322, such that the flowdisrupting feature 702 may be preferentially exposed or hidden dependingon a position (and corresponding length) of nozzle vane 260. Forexample, the flow disrupting feature 702 may be fully exposed when thesliding vane 320 is extended away from the stationary vane 310 (e.g., inthe large vane opening position). In one embodiment, the large vaneopening position may also be referred to as a first position. In yetanother example, the flow disrupting feature 702 may be exposed at thelarge vane opening position in response to engine load being less than athreshold. In this example, the threshold may be an engine load at whichengine boost may be desired.

Alternatively, the flow disrupting feature 702 on the sliding surface322 of sliding vane 320 may be fully covered or hidden by the stationaryvane 310 in the small vane opening position, wherein the sliding vane isnot extended away from the stationary vane and/or the turbine nozzle maybe at the minimum length, as depicted in FIG. 7. The small vane openingposition may also be referred to as a second position. As such, the flowdisrupting feature 702 may be hidden in the small vane opening positionin response to engine load being greater than a threshold.

Further, one or more intermediate positions may be possible such thatthe sliding vane 320 is partially extended at a location between thefirst and second position. In an example, in one or more of theintermediate positions, a portion of the flow disrupting feature 702 maybe exposed. In this way, it is possible to selectively uncover or hidethe flow disrupting feature 702 over a range of engine operatingconditions.

For example, as discussed above, during exhaust braking, the nozzlevanes may be in the large vane opening position to constrict a flow ofexhaust gases to the turbine wheel 220. That is, the sliding vane 320 isextended away from the stationary vane 310, wherein the trailing edge560 is proximal and adjacent to the inner circumference 630 of theturbine nozzle 210. During engine braking, the flow disrupting feature702 may be selectively exposed to the incoming exhaust gases of inletpassage 204. A disruption to the incoming gas flow by the flowdisrupting feature 702 may consequently lessen an intensity of shockwaves generated between the turbine nozzle 210 and turbine blades 222.In this way, the flow disrupting feature 702 may reduce the risk ofcycle fatigue in turbine blades 222.

However, exposure to the flow disrupting feature 702 may reduceaerodynamic performance when a vehicle is in a firing mode, especiallyat high engine loads when the inlet passage 204 may have a largercross-sectional area. Therefore, to reduce the aerodynamic flow lossesin the small vane opening position, where the sliding vane 320 is notextended away from the stationary vane 310, the flow disrupting feature702 may be fully and substantially covered by the sliding vane 320. Inthis way, during certain engine operating conditions, such as enginebraking, force response and shock wave induced excitation may bereduced, while desirable aerodynamic features may be maintained whenengine braking is not implemented.

Turning now to FIG. 8A, another example embodiment of the flowdisrupting feature 702 of a turbine nozzle 800 (left) and a schematicillustration of a side view of the turbine nozzle 800 (right) ispresented. In one embodiment, a nozzle vane 801 may comprise astationary vane 802 and a sliding vane 804 having planar slidingsurfaces 806 and 808, respectively. Stationary vane 802 may include asliding surface 806 in sliding contact with a sliding surface 808 ofsliding vane 804. In one embodiment, sliding surfaces 806 and 808 may besubstantially perpendicular to a planar surface 252 of nozzle wall plate250. For example, the angle between sliding surface 806 and surface 252may be between eighty and one hundred degrees. In one embodiment,sliding surfaces 806 and 808 may be parallel and planar.

In another embodiment, sliding surface 806 of stationary vane 802 andsliding surface 808 of sliding vane 804 may be cambered (e.g., curvedinstead of planar) and may be substantially complementary to oneanother. Thus, the sliding surface 808 of the sliding vane 804 may beconvex and the sliding surface 806 of the stationary vane 802 may becorrespondingly concave.

The sliding vane 804 may include flow disrupting feature 702, whereinflow disrupting feature 702 may comprise one or more parallel ornon-parallel grooves, dimples, and/or valleys. In one example, flowdisrupting feature 702 may comprise various cross-sectional shapes, suchas triangles, circles and rectangles, and any combination thereof.

In the depicted embodiment, the flow disrupting feature 702 may be on aninterior surface 810 proximal a trailing edge 860 of the sliding vane804, the interior surface 810 facing the turbine blade 222. In anotherembodiment, the flow disrupting feature 702 may be on the interiorsurface 810 proximal a leading edge 850 of the sliding vane 804. Theflow disrupting feature 702 may comprise 10% to 40% of a surface area orlength of the sliding vane 804. In addition, flow disrupting feature 702may be located substantially adjacent to a first side (not shown), thefirst side being a side facing the turbine wheel rotor. On the otherhand, the flow disrupting feature 702 may be located substantiallyadjacent to a second side (not shown), the second side being a sidefacing the shroud of the turbine (e.g., turbine 16).

In one example, the sliding vane 804 may be coupled to a shaft 818, asshown in the schematic illustration at the right in FIG. 8A. The shaft818 may be coupled to and configured to respond to an actuationmechanism 816, such as an actuation block or actuation arm (e.g.,actuation arm 340 of FIG. 3). Actuation mechanism 816 may exert anaxially directed force along an axis 830 (e.g., in a direction of thecentral axis 230 of the turbine nozzle, the central axis 230 the same asthe rotational axis of the turbine wheel) on one or more locations ofshaft 818. As such, the shaft 818, coupled to sliding vane 804, may movein at least two directions along axis 830 parallel to central axis 230(e.g., along axis 830 away from nozzle wall plate 250, and/or along axis830 towards and into nozzle wall plate 250) when the actuating mechanismis maneuvered to apply the axially directed force.

As a result, in contrast to the aforementioned embodiments of thesliding surfaces of FIGS. 3-5, in the current embodiment, the slidingvane 804 may slide in an axial direction along axis 830 on its slidingsurface 808 against sliding surface 806 of stationary vane 802. As aresult, a length of nozzle vane 801 may be adjusted by moving, e.g.sliding, the sliding vane 804 relative to the stationary vane 802. Inthis way, the geometry of nozzle vane 801 may be varied such that across-sectional area of the inlet passage, or throat, of turbine nozzle800 may be adjusted, thereby changing the volumetric flow of gas throughthe inlet passages. In one embodiment, the nozzle wall plate 250 mayinclude one or more wells 820 (e.g., recesses), wherein each well 820may comprise specific dimensions (e.g., shape and size) to substantiallyhouse and envelop sliding vane 804 on at least three sides of slidingvane 804. The wells 820 may be arranged in nozzle wall plate 250 tohouse at least one sliding vane 804, such that each well 820 maycorrespond in position to each sliding vane 804 of turbine nozzle 800.For example, as shown in FIG. 8A (right), well 820 may be positioned inwall plate 250 directly behind sliding vane 804 along axis 830. As such,moving sliding vane 804 axially along axis 830 via actuation of shaft818 may cause sliding vane 804 to either slide out and away from ortowards and into nozzle wall plate 250. In another example, wells 820may correspond in arrangement to one or more slots 330 of unison ring240 (shown in FIGS. 3 and 4). As such, when the sliding vane issubstantially retreated (e.g., recessed) into well 820 of nozzle wallplate 250, well 820 housing sliding vane 804 may be relatively flushwith the flat surface 252 of the wall plate 250.

During a first condition, sliding vane 804 may slide along axis 830 outand away from well 820. In other words, sliding vane 804 may slide awayfrom nozzle wall plate 250. When the sliding vane 804 is moved out ofwell 820, sliding vane 804 may align parallel to axis 830 (e.g., in adirection of the central axis 230 of the turbine nozzle, the centralaxis 230 the same as the rotational axis of the turbine wheel) and alonga vertical axis with stationary vane 802. As such, sliding surface 808of sliding vane 804 may slide against sliding surface 806 of stationaryvane 802. In this example, the sliding vane 804 may slide axially to aposition, wherein the sliding vane 804 may abut against and may besubstantially flush with a front-facing surface 828 of stationary vane802. In one example, the front-facing surface 828 of stationary vane 802may face the shroud side of the turbocharger.

In one embodiment, the first condition may include lower exhaust gasflow conditions, such as low engine load and low engine speed. Thus, anamount of exhaust gas flow into the turbine volute may be less thanhigher exhaust gas flow conditions (e.g., high engine load, high enginespeed, and/or during engine braking) Thus, nozzle vane 801 may be in thelarge vane opening position, wherein sliding vane 804 may be out of andaway from well 820. Moreover, sliding surface 806 of abut againstsliding surface 808 of stationary vane 802. Thus, the cross-sectionalarea of a throat area of the inlet passage 204 may be smaller ascompared to a cross-sectional area of the throat area of the inletpassage 204 when the nozzle vane 801 is in the small vane openingposition.

In one embodiment, flow disrupting feature 702 may be exposed at thelarge vane opening position during the first condition in response toengine load less than a threshold load. In this way, during the firstcondition, the flow disrupting feature 702 on the interior surface 810of sliding vane 804 may be substantially exposed to exhaust gas flow ininlet passage 204. Thus, the gas flow may contact and be disrupted bythe flow disrupting feature 702, thereby reducing force response andshock wave induced excitation during engine braking, for example. Saidanother way, the flow disrupting feature 702 may effectively disperse asudden and strong shock wave into a weakened shock wave. Consequently,an intensity of a shock wave produced during exhaust braking may bereduced on turbine blades 222, thereby reducing damage to turbine blades222.

During a second condition, sliding vane 804 may slide along axis 830into well 820. In other words, sliding vane 804 may travel towards andinto nozzle wall plate 250. In one example, when sliding vane 804 ishoused or enveloped within well 820, sliding vane 804 may besubstantially hidden such that little to no portion of the sliding vane804 and/or the flow disrupting feature 702 may intrude into a portion ofinlet passage 204. In one embodiment, the second condition may includehigh exhaust flow conditions, including high engine load and/or highengine speed. In other words, during high exhaust flow conditions, theamount of exhaust gas flow into the turbine volute or housing (e.g.,housing 202) may be greater than lower exhaust gas flow conditions(e.g., low engine load and/or low engine speed). Thus, nozzle vane 801may be in the small vane opening position, wherein sliding vane 804 maybe enveloped or housed on at least three sides within well 820. Thus,the cross-sectional area of a throat area of the inlet passage 204 maybe larger as compared to a cross-sectional area of the throat area ofthe inlet passage 204 when the nozzle vane 801 is in the large vaneopening position.

High flow conditions may also include a condition wherein engine load isgreater than the threshold load. For example, the threshold load may bean engine load at which engine boost may be desired. In this way, theflow disrupting feature 702 on the interior surface 810 of sliding vane804 may be unexposed or hidden, so that the exhaust gas flow may travelto turbine wheel 220 without disruption by interaction with flowdisrupting feature 702. In other words, sliding vanes 804 may axiallyretreat into the wells 820 of nozzle wall plate 250 to avoid efficiencypenalty due to the flow disrupting feature 702 during high exhaust flowconditions.

Now turning to FIG. 8B, a cut-out front perspective view of anotherembodiment of turbine nozzle 800 (top) and a schematic illustration of atop view of the turbine nozzle 800 (bottom) are shown. In oneembodiment, an example nozzle vane, e.g., nozzle vane 801, may comprisestationary vane 802 and sliding vane 804 having planar sliding surfaces806 and 808, respectively. In other embodiments, sliding surfaces 806and 808 may be cambered. In yet other embodiments, the sliding surfaces806 and 808 may be a combination of planar and/or cambered surfaceshaving various angles, as depicted in FIG. 8B. In one example, slidingvane 804 may be configured to move while stationary vane 802 may beimmovably attached to or integral to the annular nozzle wall plate 250.

In one embodiment, sliding vane 804 may be coupled to a nozzle wallpiece 822. In one example, nozzle wall piece 822 may be coupled tonozzle wall plate 250, such that wall piece 822 may be in directtouching contact with an interior surface (not shown) of nozzle wallplate 250.

A first surface (not shown) of the sliding vane 804 may be integrallyattached to a face-sharing, second surface (not shown) of the wall piece822. In this way, movement of the wall piece 822 may simultaneously movesliding vane 804. Similarly, adjustments to sliding vane 804 may moveconcomitantly move the wall piece 822. In one example, wall piece 822may have a surface area on the second surface substantially similar to asurface area of the first surface of the sliding vane 804, as depictedin the lower schematic illustration of FIG. 8B. In yet another example,sliding vane 804 may be reversibly coupled to wall piece 822, such thateach sliding vane 804 and/or wall piece 822 may be independentlyadjusted or actuated.

In one embodiment, the wall piece 822 may include one or more flowdisrupting features 702 on an interior surface 824 of wall piece 822. Inthis example, the flow disrupting feature 702 may be proximal andadjacent to the inner circumference 630 of wall piece 822. In anotherexample, the flow disrupting feature 702 may be disposed at anotherlocation on the wall piece 822, such as at a distance between the innercircumference 630 and outer circumference 640. In some embodiments, flowdisrupting feature 702 may include one or more parallel or non-parallelgrooves, dimples, and/or valleys. In other embodiments, flow disruptingfeature 702 may comprise various cross-sectional shapes, such astriangles, circles and/or rectangles, and any combination thereof.

As discussed above in reference to FIG. 8A, at least one of the slidingvanes 804 and/or wall piece 822 may be coupled to and configured torespond to shaft 818, as shown in FIG. 8B (bottom). Further, shaft 818may be coupled to and configured to respond to actuation mechanism 816,such as an actuation block or actuation arm (e.g., actuation arm 340 ofFIG. 3). The actuation mechanism 816 may exert an axially directed forceon one or more locations of shaft 818. As such, the shaft 818, coupledto sliding vane 804 and/or the wall piece 822, may move in at least twodirections along axis 830 (e.g., along axis 830 away from nozzle wallplate 250, and/or along axis 830 towards and into nozzle wall plate 250)when the actuating mechanism is maneuvered to apply the axially directedforce.

As shown in the lower schematic illustration of FIG. 8B, the nozzle wallplate 250 may include one or more wells 820, wherein each well 820 maycomprise specific dimensions (e.g., shape and size) to substantiallyhouse and envelop one or more sliding vanes 804 and/or wall piece 822.In one example, well 820 may comprise a generally annular shape. Well820 may be positioned within turbine nozzle 800 to house at least onesliding vane 804 and/or wall piece 822, such that at least one slidingvane 804 and/or wall piece 822 may be enclosed by well 820 on at leastthree sides when at least one sliding vane 804 and/or wall piece 822 areaxially moved into well 820 in nozzle wall plate 250.

Said another way, well 820 may be positioned within nozzle wall plate250 directly behind sliding vane 804 and/or the wall piece 822 alongaxis 830, such that moving sliding vane 804 and/or wall piece 822 viashaft 818 in an axial direction (e.g., along axis 830) may cause slidingvane 804 and/or the wall piece 822 to either slide out from or towardsinto well 820 of nozzle wall plate 250. As such, when sliding vane 804and/or the wall piece 822 substantially retreats into well 820 of nozzlewall plate 250, sliding vane 804 and/or the wall piece 822 may berelatively flush with a flat surface (e.g., surface 252) of nozzle wallplate 250.

During various operating conditions, an axial movement of one or moresliding vane 804 and/or the wall piece 822 may be adjusted. In this way,it is possible to preferentially expose and/or hide the flow disruptingfeature 702 on the wall piece 822 over a range of different operatingconditions.

For example, during a first condition, sliding vane 804 and/or wallpiece 822 may slide along axis 830 out and away from well 820. In otherwords, sliding vane 804 and/or wall piece 822 may slide away from nozzlewall plate 250. When sliding vane 804 and/or wall piece 822 move awayand out of well 820, sliding vane 804 and/or wall piece 822 may alignparallel to axis 830 (e.g., in a direction of the central axis 230 ofthe turbine nozzle, the central axis 230 the same as the rotational axisof the turbine wheel) and along a vertical axis with stationary vane802. Thus, nozzle vane 801 may be in the large vane opening position,wherein sliding vane 804 may slide out and away from well 820 and abutagainst sliding surface 808 of stationary vane 802. In other words,sliding surface 808 of sliding vane 804 may slide against slidingsurface 806 of stationary vane 802. As a result, the cross-sectionalarea of a throat area of inlet passage 204 may be smaller as compared toa cross-sectional area of the throat area of inlet passage 204 when thenozzle vane 801 is in the small vane opening position.

In one example, the first condition may include lower exhaust gas flowconditions, such as during low engine load and low engine speed. Thus,an amount of exhaust gas flow into the turbine volute or housing (e.g.,housing 202) may be less than higher exhaust gas flow conditions (e.g.,high engine load, high engine speed, and/or during engine braking) Inanother example, the first condition may include engine brakingTherefore, the larger vane opening position of nozzle vane 801 may allowmore rapid flow of lower speed exhaust flow during the first condition.

In the depicted embodiment, flow disrupting features 702 may be exposedat the large vane opening position during the first condition inresponse to engine load being less than a threshold load. As such,during the first condition, the flow disrupting feature 702circumferentially disposed around wall piece 822 may be substantiallyexposed to exhaust gas flow in inlet passage 204. In response, exhaustgas flow may contact and be disrupted by the flow disrupting feature702, thereby reducing force response and shock wave induced excitationduring engine braking, for example. Said another way, the flowdisrupting feature 702 may effectively disperse a sudden and strongshock wave into a weakened shock wave when exhaust flow travels throughthe narrowed inlet passage 204. Consequently, an intensity of a shockwave produced during exhaust braking may be reduced on turbine blades222, thereby reducing potential damage to turbine blades 222.

During a second condition, sliding vane 804 and/or wall piece 822 mayslide along axis 830 into well 820. In other words, sliding vane 804and/or wall piece 822 may travel towards and into nozzle wall plate 250.In one example, when sliding vane 804 and/or wall piece 822 are eachhoused or enveloped within well 820, sliding vane 804 and/or wall piece822 may each be substantially hidden such that little to no portion ofthe sliding vane 804 and/or wall piece 822 may intrude into a portion ofinlet passage 204. Moreover, one or more flow disrupting features 702 onwall piece 822 may also be hidden such that substantially no exhaust gasflow may fluidically contact with one or more flow disrupting features702.

In one embodiment, the second condition may include high exhaust flowconditions, wherein the amount of exhaust gas flow into the turbinevolute or housing (e.g., housing 202) is greater than lower exhaust gasflow conditions (e.g., low engine load and/or low engine speed). Thus,nozzle vane 801 may be in the small vane opening position, whereinsliding vane 804 may be enveloped or housed on at least three sideswithin well 820. Thus, the cross-sectional area of a throat area of theinlet passage 204 may be larger as compared to a cross-sectional area ofthe throat area of the inlet passage 204 when the nozzle vane 801 is inthe large vane opening position.

In this embodiment, high flow conditions may comprise high load and/orhigh temperature operating conditions. High flow conditions may alsoinclude a condition wherein engine load is greater than a thresholdload. For example, the threshold load may be an engine load at whichengine boost may be desired. In this way, the flow disrupting feature702 on wall piece 822 may be unexposed or hidden, so that the exhaustgas flow may travel to turbine wheel 220 without disruption byinteraction with flow disrupting feature 702. In other words, slidingvanes 804 may axially retreat into the wells 820 of nozzle wall plate250 to avoid efficiency penalty due to the flow disrupting feature 702during high exhaust flow conditions.

During the first and/or second condition, the axial movement of thesliding vane 804 and/or the wall piece 822 may be accomplished in two ormore steps. In other embodiments, the axial movement may be achieved inone step.

Thus, in one embodiment, an annular turbine nozzle, comprising a nozzlevane may be provided, the nozzle vane including a stationary vaneattached to a surface of a nozzle wall plate and including a firstsliding surface, and a sliding vane including a second sliding surfaceincluding a flow disrupting feature in contact with the first slidingsurface, the sliding vane positioned to slide in a direction fromsubstantially tangent to an inner circumference of the turbine nozzleand selectively uncover the flow disrupting feature.

In one example, the first sliding surface and the second sliding surfacemay be cambered surfaces. The sliding vane may be positioned to slidealong a curved line matching the cambered surfaces of the first slidingsurface and the second sliding surface. Thus, the sliding vane may slideon a curved path defined by a curvature of the first sliding surface andthe second sliding surface.

The disrupting feature may be a plurality of flow disrupting featureseach adjacent to a respective trailing edge of a plurality of nozzlevanes. In one example, the flow disrupting feature may include a grooveor a dimple. In another example, the flow disrupting feature may includetwo or more parallel grooves each having a substantially triangularcross section or substantially rectangular cross section. In yet anotherexample, the flow disrupting feature may occupy approximately 10% to 40%of the sliding vane. Further, a ratio of a maximum nozzle thickness ofthe nozzle vane to a length of a chord of the nozzle vane may be greaterthan 0.35.

The nozzle vane may be at large vane openings where the sliding vane maybe extended and moved away from the stationary vane. In the large vaneopening position, the flow disrupting feature may be uncovered andexposed to gas flow. In contrast, the nozzle vane may be at small vaneopenings where the sliding vane may not not extended away from thestationary vane. In the small vane opening position, the flow disruptingfeature may be fully covered by the sliding vane.

In another embodiment, a method may be provided, comprising adjusting aposition of a plurality of adjustable vanes radially positioned around aturbine wheel of a variable geometry turbine to a first positionexposing a flow disrupting feature on a portion of a surface of each ofthe plurality of adjustable vanes, and adjusting the position of theplurality of adjustable vanes to a second position covering the flowdisrupting feature so that the flow disrupting feature is not exposed togas flow. The plurality of adjustable vanes may include a stationaryvane portion and a sliding vane portion, and the flow disrupting featuremay be on a first sliding surface of the sliding vane. The first slidingsurface may slide against a second sliding surface of the stationaryvane. Further, the first sliding surface and the second sliding surfacemay be curved surfaces and the first sliding surface may slide againstthe second sliding surface along a curved path defined by the curvedsurfaces.

In one example, adjusting the position of the plurality of adjustablevanes to the first position may include adjusting the position of theplurality of adjustable vanes to the first position in response toengine load less than a threshold load. In another example, theadjusting the position of the plurality of adjustable vanes to thesecond position may include adjusting the position of the plurality ofadjustable vanes to the second position in response to engine loadgreater than a threshold load.

Now referring to FIG. 9, a cut-out front view of a swing vane turbinenozzle 900 of a turbocharger (left) and a schematic top-viewillustration of an actuation block 904 (right) of the swing vane turbinenozzle 900 are provided. In the swing vane turbine nozzle 900, an arrayof axially extending nozzle vanes 902 is attached to a nozzle wall 910so as to extend across one or more inlet passages 204. In one example,nozzle vanes 902 may be positioned between a hub side 912 and a shroudside 914. The hub side 912 may be a side of the turbocharger proximalturbine wheel 220 and turbine rotor, and the shroud side 914 may be aside of the turbocharger proximal turbine housing 202. In anotherexample, the nozzle wall 910 carrying the plurality of nozzle vanes 902may be at a location substantially at the hub side 912. In other words,the hub side 912 and shroud side 914 are sides relative to the hub ofthe turbine wheel 220 and the turbine shroud or housing (e.g., turbinehousing 202). Specifically, the hub side 912 is closer to the hub of theturbine wheel 220 than the shroud side 914, which is closer to theshroud or housing 202.

In this type of turbine, a size of the inlet passages 204 may becontrolled by varying the angle of the nozzle vanes relative to thedirection of exhaust gas flow through the inlet passages 204. Reducingthe cross-sectional area of one or more inlet passages 204 upstream ofthe turbine blades 222 maintains a velocity of the gas reaching theturbine 16 at a level which ensures efficient turbine operations duringlow exhaust gas volume flow.

In one embodiment, one or more nozzle vanes 902 may pivot in a firstdirection to increase a cross-sectional area of one or more inletpassages 204 upstream of the turbine 16 and may decrease the angle ofincidence of gas flowing across the turbine blades 222. Similarly,nozzle vanes 902 may pivot in an opposite, second direction to decreasethe cross-sectional area of one or more inlet passages 204 and maythereby increase an angle of incidence of gas flowing across the turbineblade 222.

In one embodiment, a first wall, such as nozzle wall 910, may be stackedon a second wall (not shown) or ring, such as unison ring 240, in anaxial direction (e.g., along a central axis 940). In one example, thesecond wall may be coupled to an actuation arm (for example, actuationarm 340 of FIG. 4) or another suitable actuation mechanism. In this way,the second wall may be rotated via the actuation arm extending in aradial direction from the second wall.

In addition, an actuation block 904 and a yoke 906 may be positionedbetween the first and second walls, and the actuation block 904 may becoupled to and configured to move with the second wall. Thus, the secondwall coupled to the actuation block 904 may rotate via an actuation armabout the central axis 940. As a result, the actuation block 904 maymove back and forth in a circumferential direction relative to thecentral axis 940.

The yoke 906 may be operably coupled to and surround the actuation block904 on at least two sides of the actuation block 904. In this way, theactuation block 904 may move the yoke 906 when the actuation block 904is moved via the actuation arm.

In one example, nozzle vanes 902 may be positioned above, relative tothe axial direction along axis 940 and in view of FIG. 9, the nozzlewall 910. Further still, a shaft, e.g., a shaft 1004 as shown anddescribed below in reference to FIG. 10, may be operably coupled to thenozzle vane 902 at a first end, wherein the first end may be proximalthe shroud side 914. The shaft may traverse the first wall and may alsobe coupled to the yoke 906 at a second end, wherein the second end maybe proximal the hub side 916 as compared to the first side. In oneembodiment, the yoke 906 may be configured to rotate the shaft. Inresponse, the rotational movement of the shaft is translated torotational movement of the nozzle vane 902 coupled to the shaft.

In other words, pivoting or rotating of nozzle vanes 902 may be achievedvia the actuation block 904 flanked by yoke 906. Specifically, theactuation block 904, operably coupled to and configured to exert forceon yoke 906, may be may be moved via the actuation arm or otherappropriate mechanism along a pre-determined path and direction. Forexample, the actuation block 904 may be moved in a first and/or seconddirection, depicted by double arrows 922, for a given distance along apath, such as a path 920. In this way, movement of the actuation block904 causing rotation of the nozzle vane 902 may affect thecross-sectional area of the inlet passage 204 and therefore alterturbine efficiency.

In an embodiment, during a first condition, the actuation block 904coupled to the nozzle vane 902 (through the yoke 906 and shaft 1004) maybe moved circumferentially in a first direction from a first position toa second position. In the second position, the plurality of nozzle vanes902 may be in a large opening position, wherein each inlet passage 204upstream of each nozzle vane 902 allows increased exhaust flow toturbine blades 222. Further, movement of actuation block 904 to thesecond position may move the nozzle vane 902 towards shroud side 914. Inone example, the actuation block 904 may be in the second positionduring high temperature and/or high load when boost in desired.

In another embodiment, during a second condition, the actuation block904 may be moved back in an opposite, second direction circumferentiallyfrom the second position. Moving back in the second direction may rotatethe plurality of nozzle vanes to a small opening position to providesmaller inlet passages 204. In this way, the nozzle vanes 902 mayconstrict a small amount of exhaust gases and increase a velocity of theexhaust gases traveling therethrough to turbine blades 222.

Moreover, an overshoot control (not shown) may be implemented when theactuation block 904 is moved past a specific location in the seconddirection, such that the actuation block 904 may be moved a thirdposition, as will be discussed in reference to FIGS. 10 and 11. Afterapplying the overshoot control and the actuation block 904 is in thethird position, the actuation block 904 may then move back to the firstposition.

Exhaust flowing through a turbine nozzle having swing-type nozzle vanes(e.g., nozzle vanes 902) may include soot and hydrocarbons that maypotentially cause increased resistance, or sticking, when pivoting orrotating the nozzle vane 902, which is especially a concern duringconditions of high engine load and/or high temperatures. In an example,one or more nozzle vanes 902 may stick on nozzle wall 910 on hub side912 more readily than the opposite facing wall of the shroud side 914.Therefore, maximizing a clearance distance between the nozzle vanes 902and nozzle wall 910 proximal the hub side 912 and/or the shroud side 914may reduce sticking of the nozzle vanes 902 during high engine loadand/or high temperature conditions.

Further, adjustments to the clearance distance on the shroud side 914and/or the hub side 912 may affect turbine efficiency. For example, areduction in the clearance distance on the shroud side 914 may improveturbine efficiency at light (e.g., lower) engine load operatingconditions while simultaneously increasing the clearance distance at thehub side 912 during high engine load operating conditions. Therefore,the reduction of the clearance distance on the shroud side 914 may alsodecrease vane sticking. In this way, shifting the plurality of nozzlevanes 902 along axis 940 away from the nozzle wall 910 on the hub side912 and towards the shroud side 914 may be desirable during both highand low engine load and/or high and low engine temperature conditions.In an example, axis 940 may be substantially orthogonal to the planaraxis of the nozzle wall 910 and the circumferential direction of amovement of the actuation block.

In an embodiment depicted at the top right of FIG. 9, an exampleactuation block 924 may have a square or rectangular-shapedcross-section. Movement of the actuation block 924 by an actuation arm(not shown) may shift the actuation block 924. In response, a yoke 926operably coupled to actuation block 924 may also shift circumferentiallyalong a path, such as path 920, causing a shaft (not shown) operablycoupled to the yoke 926 at a first end and a nozzle vane coupled to theshaft at a second end (not shown) to rotate or pivot. In this example,the yoke 926 may be only move in a circumferential direction and not anaxial direction, such as along axis 940. Thus, the square orrectangular-shaped actuation block 924 and its respectiverectangular-shaped yokes 926 may not be able to adjust the clearancedistance to achieve beneficial nozzle vane configurations.

However, axial movement along axis 940 of the nozzle vanes 902 may beachieved via actuation block 904, as depicted at the bottom right ofFIG. 9. In one example, actuation block 904 may have a substantiallyparallelogram-shaped cross-section and/or be substantially rhomboid inshape. In one example, the actuation block 904 having the rhomboid shapemay have angled sides, such that the angles between adjacent sidesand/or opposite sides of the actuation block are outside a range of80-100 degrees. In another example, the angled sides of the actuationblock 904 that face the yokes 906 may be substantially angled (e.g.,markedly greater than or less than 90 degrees).

As discussed above, in one embodiment, the actuation block 904 may beflanked on two or more sides by yoke 906, wherein the yokes 906 areconfigured to pivot one or more shafts operably coupled to nozzle vane902. In an example, one or more surfaces of the yoke 906 may be inface-sharing contact with one or more surfaces of the actuation block904. In another example, there may be a small space symmetrically spacedbetween the actuation block 904 and the yokes 906 on one or more sidesof the actuation block 904.

In one embodiment, yokes 906 may also have a parallelogram-shaped orrhomboid-shaped cross-section at least at a location adjacent to theactuation block 904. For example, the yoke 906 having the rhomboid shapemay have angled sides, such that one or more angles between adjacentsides of the yoke are outside a range of 80-100 degrees. Said anotherway, angled sides of the yoke 906 that face and are adjacent to theactuation block 904 may be substantially angled (e.g., markedly greaterthan or less than 90 degrees).

In this way, moving the rhomboid-shaped actuation block 904 in the firstdirection may move the nozzle vanes in directions along two distinctaxes (e.g., along an axis following path 920, and along axis 940). Forexample, shifting of the rhomboid-shaped actuation block 904 may cause apivotal movement of the nozzle vanes 902 about a shaft (e.g., shaft 1004shown in FIG. 10) coupled to the nozzle vane 902. In addition, shiftingof the rhomboid-shaped actuation block 904 may result in axial movementalong axis 940 to move nozzle vanes 902 substantially towards the shroudside 914. Consequently, the cross-sectional area of the inlet passage204 may be increases, thereby reducing a risk of nozzle vane stickingduring high exhaust flow conditions.

Now turning to FIG. 10, a schematic side view of the actuation block 904flanked by yoke 906 along the axial direction is shown. The actuationblock 904 may be in a first position 1010 (top schematic illustration)and/or a second position 1012 (bottom schematic illustration) along ay-axis 1016. In one example, the actuation block 904 may also be in athird position (not shown), which will be discussed in reference to FIG.11. Of note, although the first, second and third position are set alongthe linear y-axis 1016, each position may be positionedcircumferentially along an edge of the turbine nozzle such that themovement of the actuation block 904 may be circumferential as well.

In the embodiment shown, the yoke 906 may be coupled to a shaft 1004 ofthe nozzle vane 902. In one example, the actuation block 904 may be inthe first position 1010, wherein the first position 1010 of theactuation block 904 rotates the yoke 906 to swing the nozzle vanes tothe small opening position. In other words, the first position may causethe nozzle vanes to be positioned in a way to reduce a cross-sectionalarea of the inlet passage and thus constrict a flow of exhaust gases tothe turbine wheel. In this position, a length of the nozzle vanes(defined from the leading edge to the trailing edge) may besubstantially tangent to the central axis 940. The first position mayincrease the velocity of the gases during low engine load, low enginespeed, and/or low engine temperature operating conditions through asmaller cross-sectional area of the inlet passages 204 to the turbineblades.

In another example, the actuation block 904 may be in the secondposition 1012, wherein the actuation block 904 may move in the firstdirection (as discussed in reference to FIG. 9) to pivot the pluralityof nozzle vanes 902 to the large opening position. As a result, inletpassages 204 may have a larger cross-sectional area to allow a greateramount of exhaust gases to flow to the turbine blades. In one example,the actuation block 904 may be in the second position during high engineload, high engine speed, and/or high engine temperature operatingconditions. In the second position, the length of the nozzle vanes maybe aligned radially with respect to the central axis 940.

As described briefly above, the actuation block 904 may be coupled toand configured to produce a bias pressure 1005, denoted as an arrow inthe bottom schematic illustration of FIG. 10, on one or more locationsof one or more yokes 906 when actuation block 904 is moved from thefirst position 1010 to the second position 1012. The bias pressure 1005may be produced on a location of yoke 906 adjacent to a corner of theactuation block 904 that is contacted when the actuation block 904 movesin at least one direction.

As such, when the actuation block 904 is in the first position 1010,depicted in the top schematic illustration of FIG. 10, a clearancedistance 1006 between the nozzle vane 902 and the nozzle wall 910 of thehub side 912 may be substantially similar to a clearance distance 1008between the nozzle vane 902 and shroud side 914. However, when theactuation block 904 is moved to the second position 1012 (depicted inthe bottom schematic illustration of FIG. 10), the actuation block 904may produce the bias force or pressure 1005 on an adjacent corner of oneof a yoke 906. The bias pressure 1005 experienced by the yoke 906 maycause shaft 1004 of the nozzle vane 902 to move in the axial directionalong axis 940.

In one example, all nozzle vanes of the turbine nozzle may movesimultaneously along axis 940 to the shroud side 914. As a result, theplurality of nozzle vanes 902 may be moved away from nozzle wall 910during certain operating conditions. In this way, it is possible toreduce sticking of the nozzle vanes 902 during high engine load, highexhaust flow and/or high engine temperature conditions, while increasingturbine efficiency during low exhaust flow conditions. In sum, anactuation block having a parallelogram-shape and/or rhomboid shape(e.g., actuation block 904) may be provided to control the clearancedistance on the shroud side 914, i.e. the distance between nozzle vanes902 and turbine housing 202, and hub side 912, i.e. the distance betweenthe turbine nozzle vane 902 and the nozzle wall 910.

Turning now to FIG. 11, a method 1100 for controlling the clearancedistances of nozzle vane of the turbine nozzle of FIGS. 9 and 10 duringa first and a second condition is disclosed. During the first condition,such as during high engine temperature and/or high engine load operatingconditions, the plurality of nozzle vanes 902 may swing in a firstdirection (described as the first direction in reference to FIGS. 9 and10) in order to allow a larger amount of exhaust gases to flow throughto the turbine wheel 220 and turbine blades 222. The first condition mayalso include a condition when engine load is greater than a thresholdload. For example, the threshold load may be an engine load at whichengine boost may be desired. Thus, the actuation block 904 may move inthe first direction from the first position to the second position. As aresult, actuation block 904 may shift yokes 906 to rotate the nozzlevanes 902 to the large opening position. The large opening position ofthe nozzle vanes may lead to increases in cross-sectional area of one ormore inlet passages 204, allowing a larger amount of exhaust gases torotate turbine wheel 220 and provide increased engine power.

On the other hand, during a second condition, such as during low enginetemperature and/or low engine load operating conditions, actuation block904 may be moved in an opposite, second direction (described as thesecond direction in reference to FIGS. 9 and 10) relative to the secondposition, to a third position past the first position to reduce across-sectional area of a throat opening of inlet passages 204. As aresult, the nozzle vanes 902 may move to the small opening position. Thesmall opening position may allow an increase of the velocity of exhaustgases through the constricted inlet passages 204 to the turbine wheel220 during low exhaust flow conditions. The second condition may alsoinclude a condition when engine load is less than the aforementionedthreshold load.

In one embodiment, an overshoot control may be executed when theactuation block 904 is moved past a specific location in the seconddirection, such that the actuation block 904 may be moved to a thirdposition, such as third position 1014 of FIG. 10. After applying theovershoot control and the actuation block 904 is in the third position,the actuation block 904 may then move back to the first position. Theovershoot control may be included in order to maintain the small openingposition to constrict exhaust gas flow while producing the bias pressure1005 on yoke 906 to move the nozzle vanes 902 in the axial directionalong axis 940. In this way, during the second condition, the pluralityof nozzle vanes may be in the small opening position to increase turbineefficiency while minimizing shroud side clearance to reduce nozzle vanesticking during high engine temperature conditions.

Thus, at 1102, engine operating conditions and/or the position of anactuation block (e.g., actuation block 904) may be determined. Forexample, engine load, engine speed, boost pressure, intake air massflow, turbocharger speed, and exhaust temperature may be measured orcalculated by a controller, such as controller 12 of FIG. 1. In oneexample, these conditions may be used to determine if a clearancedistance of the nozzle vanes (e.g., nozzle vanes 902) may be adjusted.For example, it may be beneficial for the clearance distance of thenozzle vanes to be moved closer to the shroud side (e.g., shroud side914) of the turbine (e.g., turbine 16) during high engine temperaturesto reduce risk of nozzle vane sticking.

In another example, the position of the actuation block may also bedetermined at 1102. The actuation block may be in a first position(e.g., first position 1010 of FIG. 10), wherein the first position ofthe actuation block rotates a yoke (e.g., yoke 906) to swing the nozzlevanes to the small opening position. In other words, the first positionmay cause the nozzle vanes to be positioned in such a way to constrict aflow of exhaust gases to a turbine wheel (e.g., turbine wheel 220) andturbine blades (e.g., turbine blades 222). As such, the first positionmay increase a velocity of the exhaust gases during low engine loadand/or low engine temperature operating conditions through a smalleropening or cross-sectional area of the inlet passages (e.g., inletpassages 204). In one example, a position sensor (not shown) or anothersuitable sensing device may determine a position of the actuation block904.

At 1104, it is confirmed if a first condition, including high exhaustflow, high load and/or high temperature conditions, is present, suchthat a larger cross-sectional area of the inlet passage(s) for exhaustgas to travel therethrough to the turbine wheel may be desirable. In oneexample, the first condition includes a condition wherein engine load isgreater than a threshold load, such as the threshold load describedabove in FIGS. 9 and 10. In this example, the threshold load may be anengine load at which engine boost may be desired. If the aforementionedcondition(s) are confirmed, a larger amount of exhaust gases may beproduced and routed to the turbine wheel.

Thus, at 1106, the actuation block is moved circumferentially in thefirst direction to a second position (e.g., second position 1012 of FIG.10). The movement of the actuation block to the second positionsimultaneously causes the nozzle vanes to pivot to provide a relativelylarger inlet passage, and produce a bias pressure, such as the biaspressure 1005 of FIG. 10, to push the nozzle vanes along an axis (e.g.,axis 940) at 1108. As described in FIG. 10, the bias pressure is appliedin the axial direction such that the nozzle vanes move axially towardthe shroud side (e.g. shroud side 914) of the turbine. In other words,moving the rhomboid-shaped actuation block in the first direction shiftsthe nozzle vanes in two directions, resulting in both a pivotal movementof the nozzle vanes to increase the cross-sectional area of the inletpassage and an axial movement to move the nozzle vanes 902 substantiallytowards the shroud side 914 to reduce the risk of vane sticking duringhigh flow conditions.

If the first condition at 1104 is not confirmed, then it is determinedif a second condition is present at 1110. For example, the secondcondition may comprise low engine temperature and/or low engine loadoperating conditions. The second condition may also include a conditionwhen engine load is less than the threshold load. In this example, thethreshold load may be an engine load at which engine boost may not bedesired. During the second condition, lower exhaust flow may be routedto the turbine, therefore a smaller inlet passages upstream of theturbine is desired to increase a velocity of the exhaust gases to powerthe turbine wheel. In one example, the actuation block may move back tothe first position, wherein the first position of the actuation blockrotates the yoke to swing the nozzle vanes to the small openingposition. However, in this example, movement of the actuation block backto the first position may not exert the bias pressure on the yoke toenable an axial force upon the shaft (e.g., shaft 1004) due to anorientation and shape of the actuation block. As a result, undesirednozzle vane sticking may occur.

Thus, at 1112, during the second condition, an overshoot control isapplied, wherein the actuation block may be moved in the opposite,second direction past the first position to a third position (e.g.,third position 1014 of FIG. 10). In one example, the first position maybe between the second position and the third position (along thecircumferential line of travel of the actuation block). At 1114, in thethird position, the plurality of nozzle vanes may pivot into a smallerinlet passage configuration, such as the small opening position. Thesmall opening position may allow an increase of the velocity of exhaustgases through the constricted inlet passages to the turbine wheel.

In one example, after the actuation block is in the third position, theactuation block moves back in the first direction to the first positionat 1116. Movement in the first direction back to the first positionproduces the bias pressure or force on the plurality of shafts to movethe nozzle vanes back against the shroud side. Therefore, the movementof the actuation block 904 in the first direction may minimize theclearance distance (e.g., distance 1008 of FIG. 10) at the shroud side.Further, at 1116, the plurality of nozzle vanes may remain in the smallopening position.

Thus, a method for a turbine nozzle may be provided, comprising during afirst condition, moving an actuation block coupled to a nozzle vane ofthe turbine nozzle from a first position to a second position to openthe nozzle vane and move the nozzle vane against a shroud-side wall ofthe turbine nozzle, and during a second condition, moving the actuationblock from the second position to a third position, the first positionbetween the second position and the third position, and then back to thefirst position to close the nozzle vane and move the nozzle vane backagainst the shroud-side wall. In one embodiment, the actuating block maybe shaped as a rhomboid. Further, the actuation block may be coupled tothe nozzle vane through a pivotable yoke and rotatable shaft, thepivotable yoke surrounding two oppositely facing sides of the actuationblock.

In one example, the first condition may include when engine load isgreater than a threshold load while the second condition includes whenengine load is less than the threshold load. In addition, moving theactuation block may include moving the actuation block in acircumferential direction relative to a central axis of a turbine wheel,the turbine nozzle surrounding the turbine wheel and sharing the centralaxis with the turbine wheel, and consequentially moving the yoke in thecircumferential direction and an axial direction, the axial directiondefined in a direction of the central axis.

The technical effect of a method for adjusting a distance between aplurality of nozzle vanes and a shroud side of a turbine may reducesticking of the nozzle vanes during high engine load and/or high enginetemperature conditions, while increasing aerodynamic efficiency of theangle of incidence during low engine load and/or low engine temperatureconditions. Further, the disclosed system having cambered slidingsurfaces and a desirable ratio of thickness to chord length also providea reduced radial displacement of a sliding vane when adjusting a throatarea (e.g., cross-sectional area of inlet passages) between the slidingand the stationary vanes, as well as increased aerodynamic efficiencydue to a desirable angle of incidence. In this way, the cambered slidingsurfaces of the nozzle vanes reduce intrusion of the nozzle vanes intoturbine housing (e.g., volute) at a leading edge of the sliding nozzlevane, thereby permitting compact packaging in most existing variablegeometry turbines.

Note that the example control and estimation routines included hereincan be used with various engine and/or vehicle system configurations.Further, the methods described herein may be a combination of actionstaken by a controller in the physical world and instructions within thecontroller. The control methods and routines disclosed herein may bestored as executable instructions in non-transitory memory and may becarried out by the control system including the controller incombination with the various sensors, actuators, and other enginehardware. The specific routines described herein may represent one ormore of any number of processing strategies such as event-driven,interrupt-driven, multi-tasking, multi-threading, and the like. As such,various actions, operations, and/or functions illustrated may beperformed in the sequence illustrated, in parallel, or in some casesomitted. Likewise, the order of processing is not necessarily requiredto achieve the features and advantages of the example embodimentsdescribed herein, but is provided for ease of illustration anddescription. One or more of the illustrated actions, operations and/orfunctions may be repeatedly performed depending on the particularstrategy being used. Further, the described actions, operations and/orfunctions may graphically represent code to be programmed intonon-transitory memory of the computer readable storage medium in theengine control system, where the described actions are carried out byexecuting the instructions in a system including the various enginehardware components in combination with the electronic controller

This concludes the description. The reading of it by those skilled inthe art would bring to mind many alterations and modifications withoutdeparting from the spirit and the scope of the description. For example,I3, I4, I5, V6, V8, V10, and V12 engines operating in natural gas,gasoline, diesel, or alternative fuel configurations could use thepresent description to advantage.

The following claims particularly point out certain combinations andsub-combinations regarded as novel and non-obvious. These claims mayrefer to “an” element or “a first” element or the equivalent thereof.Such claims should be understood to include incorporation of one or moresuch elements, neither requiring nor excluding two or more suchelements. Other combinations and sub-combinations of the disclosedfeatures, functions, elements, and/or properties may be claimed throughamendment of the present claims or through presentation of new claims inthis or a related application. Such claims, whether broader, narrower,equal, or different in scope to the original claims, also are regardedas included within the subject matter of the present disclosure.

The invention claimed is:
 1. A turbine nozzle, comprising: a nozzle vaneincluding: a stationary vane attached to a surface of a nozzle wallplate and including a first sliding surface; and a sliding vaneincluding a second sliding surface including a flow disrupting featurein contact with the first sliding surface, the sliding vane positionedto slide in a direction from substantially tangent to an innercircumference of the turbine nozzle and selectively uncover the flowdisrupting feature.
 2. The nozzle of claim 1, wherein the first slidingsurface and the second sliding surface are cambered surfaces and whereinthe sliding vane is positioned to slide along a curved line matching thecambered surfaces of the first sliding surface and the second slidingsurface.
 3. The nozzle of claim 1, wherein the sliding vane slides on acurved path defined by a curvature of the first sliding surface and thesecond sliding surface.
 4. The nozzle of claim 1, wherein the flowdisrupting feature is a plurality of flow disrupting features eachadjacent to a respective trailing edge of a plurality of nozzle vanes.5. The nozzle of claim 1, wherein the flow disrupting feature includes agroove or a dimple.
 6. The nozzle of claim 1, wherein the flowdisrupting feature includes two or more parallel grooves each having asubstantially triangular cross section or substantially rectangularcross section.
 7. The nozzle of claim 1, wherein the flow disruptingfeature occupies approximately 10% to 40% of the sliding vane.
 8. Thenozzle of claim 1, wherein at large vane openings where the sliding vaneis extended and moved away from the stationary vane, the flow disruptingfeature is uncovered and exposed to gas flow.
 9. The nozzle of claim 1,wherein at small vane openings where the sliding vane is not extendedaway from the stationary vane, the flow disrupting feature is fullycovered by the sliding vane.
 10. The nozzle of claim 1, wherein a ratioof a maximum nozzle thickness of the nozzle vane to a length of a chordof the nozzle vane is greater than 0.35.
 11. A method, comprising:adjusting a position of a plurality of adjustable vanes radiallypositioned around a turbine wheel of a variable geometry turbine to afirst position exposing a flow disrupting feature on a portion of asurface of each of the plurality of adjustable vanes; and adjusting theposition of the plurality of adjustable vanes to a second positioncovering the flow disrupting feature so that the flow disrupting featureis not exposed to gas flow.
 12. The method of claim 11, wherein theadjusting the position of the plurality of adjustable vanes to the firstposition includes adjusting the position of the plurality of adjustablevanes to the first position in response to engine load less than athreshold load.
 13. The method of claim 11, wherein the adjusting theposition of the plurality of adjustable vanes to the second positionincludes adjusting the position of the plurality of adjustable vanes tothe second position in response to engine load greater than a thresholdload.
 14. The method of claim 11, wherein the plurality of adjustablevanes includes a stationary vane portion and a sliding vane portion,wherein the flow disrupting feature is on a first sliding surface of thesliding vane portion, and wherein the first sliding surface slidesagainst a second sliding surface of the stationary vane portion.
 15. Themethod of claim 14, wherein the first sliding surface and the secondsliding surface are curved surfaces and wherein the first slidingsurface slides against the second sliding surface along a curved pathdefined by the curved surfaces.